* Chen appeals for help in call to U.S. congress hearing
* Republicans criticize Obama's handling of the case
* U.S. officials continue talks with Beijing on Chen's fate
By Chris Buckley and Paul Eckert
BEIJING/WASHINGTON, May 3 (Reuters) - Blind Chinese dissident Chen Guangcheng made a dramatic plea for help in a cellphone call to a U.S. congressional hearing from his hospital bed in Beijing, raising the pressure on President Barack Obama over his administration's handling of the case.
Chen, a self-taught legal activist, sheltered in the U.S. Embassy for six days until Wednesday. He left the embassy shortly before U.S. Secretary of State Hillary of Clinton arrived in Beijing for talks aimed at improving economic and strategic relations between the two superpowers.
But within hours, Chen changed his mind about a deal that U.S. officials had said would allow him to relocate with his family and pursue his studies at a university.
Thursday's U.S. congressional hearing on Chen's case took a dramatic turn when a witness called the dissident on his cellphone and relayed his appeal for help to members of Congress and the media.
"I want to come to the U.S. to rest. I have not had a rest in 10 years," Chen said, according to a translation by Bob Fu, the president of Texas-based religious and human rights group ChinaAid. Fu held his cellphone to the microphone so that Chen could be heard, and translated his words.
Speaking from a Beijing hospital where he was reunited with his wife on Wednesday and where he was being treated for a foot injury, Chen said he wanted to meet Clinton to ask her for help and to thank her.
He said villagers who had helped him were "receiving retribution" and he was most concerned about the safety of his mother and brothers, according to Fu's translation.
"I'm really scared for my other family members' lives," Chen said. "They have installed seven video cameras and are in my house."
A pack of camera crews and reporters have been waiting outside Chen's hospital in Beijing, kept away from the entrance by police. Radio Free Asia quoted Chen as saying he had received no visits from friends and his phone service was unreliable.
U.S. officials have defended their handling of the case, but Republicans and Chen's supporters were critical, saying the White House must ensure Chen's safety. He sought refuge in the U.S. Embassy after escaping from house arrest in a village in rural Shandong province on April 22.
Republican presidential candidate Mitt Romney said if the reports were accurate, the U.S. Embassy "failed to put in place the kind of verifiable measures that would ensure the safety of Mr Chen and his family.
"If these reports are true, this is a dark day for freedom, and it's a day of shame of the Obama administration," Romney said during an event in Virginia on Thursday as he campaigns for the November election.
China's Foreign Ministry declined to comment on Chen's request to leave the country and repeated its criticism of the way the United States had handled the issue as "unacceptable". China has demanded an apology from the United States.
Representative Ileana Ros-Lehtinen, chairwoman of the House of Representatives Foreign Affairs Committee, said: "It should have been obvious to U.S. officials all along that there is no way to guarantee Mr Chen's safety so long as he is within reach of the Chinese police state."
Some rights activists were also critical. "We have learned that when people come to the United States Embassy they are not in fact 100 percent safe," said Reggie Littlejohn, president of the advocacy group Women's Rights Without Frontiers.
"They can be turned over to the Chinese authorities from whom they were attempting to escape," she told a news conference in Washington.
Fu of ChinaAid said Chen had told him that while he was at the embassy, U.S. officials conveyed a message that if he didn't leave that day his family would be returned to the village where his family had lived "in hell" for years. Fu quoted Chen as saying: "I felt great pressure to leave."
Chen, 40, is a legal activist who campaigned against forced abortions under China's "one-child" policy.
U.S. officials say Chen left the embassy of his own free will because he wanted to be reunited with his wife and children. They said he wanted to remain in China and never asked for asylum.
"He knew the stark choices in front of him," U.S. Ambassador Gary Locke told reporters in Beijing on Thursday. "He knew and was very aware that he might have to spend many, many years in the embassy. But he was prepared to do that ...
"And he was fully aware of and talked about what might happen to his family if he stayed in the embassy and they stayed in the village in Shandong province."
In an interview with CNN, Ambassador Locke said U.S. officials had spoken to Chen on Thursday. Asked if the United States could promise Chen that it would get him out of China, Locke replied: "We are not about to make promises that we cannot keep."
Frank Wolf, a Republican representative from Virginia and strident critic of Chinese rights practices, said the administration was at best "naive" in its handling of the case.
"The administration has a moral obligation to protect Chen and his family. To do anything less would be scandalous," Wolf said.
Clinton and Treasury Secretary Timothy Geithner were scheduled to hold further talks in Beijing on Friday. Washington had hoped the talks would secure more cooperation from China on trade and international flashpoints such as North Korea, Iran and Syria.
John Bolton, a former U.N. ambassador under President George W. Bush and now an informal adviser to the Romney campaign, told Fox News the situation was "a train wreck in process."
White House spokesman Jay Carney said the administration was aware that Chen and his wife had had a change of heart and that State Department officials were in discussions with Chen, his wife and Chinese officials.
Carney pushed back against critics who have suggested that U.S. diplomats, seeking to defuse the situation with Beijing, had pressured Chen into his original decision to stay in China.
"And at every opportunity he expressed his desire to stay in China, reunify with this family, continue his education and work for reform in his country," Carney said. "There was no pressure of any kind placed on him by U.S. officials."
The Chen case came at an tricky time for both nations: Obama is anxious to portray an image of strength in his dealing with foreign countries as he prepares for the election and China is engaged in a leadership change later this year.
The carefully choreographed power transition in Beijing has already been jarred by the downfall of ambitious senior Communist Party official Bo Xilai after he was caught up in a scandal linked to the apparent murder of a British businessman.